Cardiac function in borderline hypothyroidism: a study by pulsed wave tissue Doppler imaging

Objective: In subclinical hypothyroidism (SH). impaired diastolic function has been documented at rest and on effort, while systolic dysfunction has only been assessed on effort. Design: The aim of the present study was: (a) to further assess systolic function at rest in SH: and (b) to ascertain whether cardiac dysfunction could precede TSH increase in euthyroid patients with a high risk of developing SH. Methods: We studied 32 patients with classical Hashimoto's thyroiditis (22 with increased serum TSH (> 3 mU/ml - group A), and 10 with normal serum TSH (< 3 mU/ml - group B)); a third group (C), which included 13 healthy controls. All subjects underwent pulsed wave tissue Doppler imaging (PWTDI) to accurately quantify the global and regional left ventricular function. Results: When compared with group C. PWTDI indices showed that in both groups A and B there was a significant impairment of systolic ejection (P < 0.001 and P < 0.05, respectively), a delay in diastolic relaxation (P < 0.001, and P < 0.05, respectively) and a decrease in the compliance to the ventricular filling (P < 0.05). Several significant correlations were found between PWTDI parameters and serum-free T-3 and T-4 and TSH concentrations. Conclusion: PWTDI is a sensitive technique that allows detection of both diastolic and systolic abnormalities. not only in patients with SH, but also in euthyroid subjects with a high risk of developing thyroid failure. Futhermore. the significant correlations of several PWTDI indices with serum FT3 and TSH concentrations strongly Support the concept of a continuum spectrum of it slight thyroid failure in autoimmune thyroiditis extending to subjects with serum TSH still within the normal range.